Product and process for producing a container cured illuminant composition

ABSTRACT

ILLUMINANT FUELS AND OXIDIZERSS ARE ADDED TO CRUSHABLE CAPSULES CONTAINING CURABLE, ILLUMINANT BINDERS AND TO CRUSHABLE CAPSULES CONTAINING CURING AGENTS FOR THE ILLUMINAANT BINDERS TO FORM A HOMOGENEOUSLY MIXED, FLOWABLE POWDER, ILLUMINANT COMPOSITION. THIS COMPOSITION IS DISPENSED INTO ILLUMINANT CONTAAINERS WHERE A CAPSULE RUPTURING PRESSURE IS APPLIED RUPTURING THE CAPSULES IN THE COMPOSITION. THIS RESULTS IN THE LIQUID BINDERS AND LIQUID CURING AGENTS BEING RELEASED AND DISPERSED THROUGHOUT THE COMPOSITION AND INTERACTING AND FORMING A CONTAINER CURED ILLUMINANT.

3,728,172 PRODUCT AND PROCESS FOR PRODUCING A CONTAINER CURED ILLUMINANTCOMPOSITION David R. Dillehay, Herman F. Krackenberger, and Howard C.Havron, Marshall, Tex., assignors to Thiokol Chemical Corporation,Bristol, Pa. No Drawing. Filed Dec. 15, 1970, Ser. No. 98,481

Int. Cl. C06d 1/10 U.S. Cl. 149-19 28 Claims ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a product and process for making a container curedilluminant. Particularly, the invention relates to the preparation of anilluminant composition containing illuminant fuels and oxidizers mixedwith crushable capsules of binders and crushable capsules of curingagents to form a flowable powder composition which is dispersed intocontainers and pressed to form a container cured illuminant.

Description of the prior art Illuminants presently are manufactured bythe batch process where the desired amounts of illuminant fuels,oxidizers, liquid binders, liquid curing agents and =fillers are mixedtogether in bulk quantities. This composition is then dispensed by smallincrements into illuminant containers and pressed to form the finishedproduct.

The above batch process has not been an entirely satisfactory method ofpreparing illuminants. One of the serious problems is that batch mixingexposes personnel to bulk quantities of hazardous material at the mixer,during transfer and at the press. This process also necessitates aremote facility for manufacturing the illuminant to further insuresafety.

Other undesirable aspects of the batch mixing process are the variationsin the physical properties of illuminants made by this process. If thecuring times of the illuminant compositions are varied, burning ratesand candlepowers of the illuminants will also vary. This problem ismagnified by the fact that the illuminant compositions have a short potlife requiring very precise mixing times, dispensing times and pressingpressures or the physical properties of the illuminant will greatly varyfrom batch to batch. The dispensing times will by necessity varysomewhat between containers since all the containers are not filled atone time. Therefore, the containers filled at the beginning of theoperation are filled with illuminant which is not pot cured as long asthe containers are filled later in the operation. This results invariations in container filling resulting in many overfills, andvariations in burn rate and candlepower between containers of the samebatch.

BRIEF SUMMARY OF THE INVENTION The object of the present invention isdirected to providing an improved product and process for producing acontainer cured illuminant.

3,728,172 Patented Apr. 17, 1973 The objects of the invention may beaccomplished by use of crushable capsules of both binders and curingagents in illuminant compositions. Each material in the compositionincluding the illuminant fuels, oxidizers, and fillers may be separatelyfed into a system for combining the materials in single containerdispensing amounts and then this small amount of material is dispensedinto a single container where a capsule crushing amount of pressure isapplied resulting in releasing the binders and curing agents into thesurrounding materials Where they interact, forming a container curedilluminant.

The use of this process provides for each container of illuminant to beuniformly cured and pressed in the container under uniform conditions.This process eliminates variations in burning rates and candlepowerbetween different batches of illuminates and also between containersfilled from the same batch of material. Furthermore, this processeliminates the hazard of pre-rnixing bulk quantities of the illuminantcomposition before dispensing into the containers. Since only one singlecontainer mixture will exist at any one time no serious hazard ispresented. Therefore, this process minimizes personnel exposure to thehazardous materials and protects the manufacturing equipment fromserious fires.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnesium used in theilluminant composition is preferably in a particulate form of metalfuel. While magnesium is the preferred fuel, it may be desirable in somecases to use other metals used in pyrotechnic devices as metal fuels inplace of some of the magnesium, e.g. aluminum, or magnesium-aluminum andzirconium and their hydrides. The metal fuel is preferably used inamounts from about 40 to 60% by weight of the composition.

Sodium nitrate is preferably used as the oxidizer for the magnesium fuelin the illuminant composition. However, in some cases it may beadvantageous to use another metal nitrate, e.g., lithium nitrate, takingdue precautions in handling the latter because of its greatlyhydroscopic nature. When yellow light is not desired, color producingmetal nitrates, such as barium or strontium nitrate, may be usedadvantageously. The metal nitrate is preferably used in at least astoichiometric amount relative to the metal fuel ingredient of theilluminant composition. The most preferable amounts is from about 30 to50% based on the total weight of the composition.

The liquid polymeric binder material used in practicing the inventionpreferably is a mixture of liquid polyester polymer and liquid epoxyresin. All the liquid ingredients including the liquid binders, curingagents and curing accelerators are used in encapsulated form in order toaccomplish the objectives of this invention. The encapsulation of theseliquids may be by any of several known procedures. One such method isdescribed in U.S. Pat. 3,041,289 and is herein incorporated byreference. Other such suitable encapsulation methods are described inU.S. Pat. 2,969,331 and U.S. Pat. 2,800,458. In these procedures thematerial to be encapsulated is dispersed or emulsified in a liquidmedium containing the wall material. The Wall material is then caused toseparate out in a viscous form, deposited or Wrapped around the materialto be encapsulated, and later solidified and hardened. The corematerials of the individual capsules are removed by the physicalfracture of the capsules. The encapsulated liquid polyester polymer maybe a carboxyl-terminated polyester polymer of a saturated aliphaticdiol, a dicarboxylic acid free from ethylenic unsaturation, or apolyfunctional compound free from ethylenic unsaturation and containingat least three functional groups selected from the group consisting ofpolyols, polycarboxylic acids and polycarboxylic acid anhydrides. Thepolymeric polyester may be liquid at a temperature between about 25 C.and glycol, etc. Similarly, other dihydric phenols may be emabout 50 C.,having an acid content between about 0.1 ployed, including resorcinol,catechol, hydroquinone, 4,4- and about 1.5 milliequivalents per gram, anaverage of dihydroxybenzophenone, 1,1 bis-(4-hydroxyphenyl)-bubetweenabout 2.5 and about 15 carboxylic groups per tane,1,S-dihydroxynaphthylene, etc. It is understood that molecule, anaverage molecular weight between about 5 the epoxy resins formed fromthe various reactants men- 700 to about 10,000 and free from hydroxylgroups. Such tioned above are not necessarily equivalent and,furtherpolymers are known and are taught, for example, in US. more, thatthe exact composition of the epoxy resins are Pat. 3,182,041,incorporated herein by reference. Predependent upon the molecularproportions of the epoxy ferred liquid polyester polymers are thosehaving a high compound and dihydric phenol employed in its preparaoxygencontent combined with the carbon and hydrogen tion. Preferred liquidepoxy resins are those having an content of the polymer. Especiallypreferred are liquid epoxide equivalent {weight of resin in gramscontaining polyester polymers having a carbon to hydrogen to oxy- 1 gramof epoxy resin) of about 175 to 210 and a vis gen ratio of about 2 to2.55 to 1 and a viscosity at 25" C. cosity of about 500 to 900centipoises. When a solvent is of 480 to 520 poise. Polyesters preparedfrom saturated used, organic solvent such as toluene, xylene andketones, diacids, e.g. saturated fatty acids, such as suecinic and e.g.acetone, are preferably used. The liquid epoxy resin glutaric acids andtheir anhydrides are especially prenormally serves as a curing agentcarrier for the polyester ferred. Also capsules which are especiallypreferred conpolymer. While the liquid epoxy resins do not necessarilytain polyester resins represented by the formula cure with the polyesterpolymers, these resins may be 0 cured by the addition of epoxy resinscuring agents, e.g.

|| anhydrides or dianhydrides. The curing of these epoxy E resins giveadded strength to the cured illuminant.

HO- cH-CH2-O-(5 J-O-CHCHZ-O-i JC=C H Capsules which are preferredcontain a liquid carrier Ha Ha for the curing agent. A liquid carrierespecially preferred is diglycidyl ether of bisphenol A resinrepresented by n the formula where n is greater than zero. Thispolyester resin is sold where n is greater than zero. This material issold under under the trademark Aropol 72-4-MC. The capsule conthetrademark Epon 828. The capsule containing the taining this resincontains in addition about 10 to 50% above resin contains in additionabout 10 to 14% curing monomeric styrene based on the total weight ofthe polyagent preferably 12% benzoyl peroxide based on the total esterresin, preferably about 25 to 35%; about 4 to 6% weight of the resinousliquid carrier. The crushable caprutile filler, preferably 5% titaniumdioxide; and 4 to 6% sules containing the above material are sold underthe cure accelerator, preferably 5% N,N-dimethyl-ptoluidine, trademarkPEP-512 by National Cash Register Corpobased on the total weight of theunsaturated polyester ration. The preferable amount of these capsules isfrom resin. The crushable capsules containing the above mateabo t 1 t 5%ba d on th t t l weight f th composirials are sold under the trademarkPEP-512 by National tion.

Cash Register Corporation. The preferable amount of The preferred ratioof the capsules containing the curthese capsules is from about 2 to 8%based on the to al able binder, fillers and cure accelerators to thecapsules weight of the composition. containing the curing agent andliquid carrier is 2:1.

The binder mater l is accelerated in its Curing y the By using anon-line blender or mixer, small container a d t of a Small amount ofcatalyst for the curing size mixes may be made, eliminating thenecessity of mixagetlt- Preferably, the curing Tate catalyst isN!N-dimething large amounts of the illuminant fuels and oxidizersyl-p-toluidine. The amounts of catalyst used then controls t one ti therate at which the cure occurs. The container size of mixed powderedilluminant is Generally, it is desirable that the amount of curingdispensed into an illuminant container where a capsule agent used bePresent in at least stoichiometric amount rupturing and consolidatingamount of pressure is applied relative to the polyester p y in Order toprovide to form the illuminant. The capsule rupturing and conplete cureof the polyester polymer. Polyester resin cursolidating pressure may befrom about 2,000 p.s.i. to ing agents, such as polyfunctionalaziridines, e.g. trifunc- 10,000 p.s.i., preferably 5,000 psi. to 7,000p.s.i. tional derivatives of ethylenimine and other alkylenimine Thereare many automatic powder loading and derivatives as taught in 3,182,041may 2 usedsolidating machines available which may be used. Such Thosecuring agents Preferred are benzoyl peroxlde machines are described inus. Pat. 2,300,250, US. Pat. methyl ethyl ketone peroxide. Especiallypreferred is 2,834,383 and Us Pat. 2,901,209. benzcyl Peroxlde' 6 Whilespecific ingredients have been used to describe Liquid epoxy resins andsolutions herein are Well known, and are also used in capsule form asliquid carriers for the curing agents to accomplish the objects of thisinvention. The epoxy resins are formed by the reaction of a 1,2-epoxycompound and a dihydric phenol. The

and illustrate the invention, it is to be understood that otheringredients having equivalent properties may be substituted for thoseshown in order to practice the invention and to obtain the benefits andadvantages thereof.

preferred 1,2-epoxy resins are prepared by the reaction of The examplesare Submltted t0 epichlohydrin with bisphenol-A(2,2-bis(4-hydroxyphenfurther 11lustr1te ttlemventlon.

yl)-propane), generally in alkaline solution, such com- The mventlon111l1trated y means of a representapounds in ludin f a le, polyglycidylther of thtive, commercially available capsular adhesive made up yleneglycol, propylene glycol, trimethylene glycol, diof two types ofcapsules. One capsule contains a diglycidyl ethylene glycol, triethyleneglycol, glycerol, dipropylene ether of bisphenol A resin represented bythe formula CHa 6 where n is greater than zero and, in addition, thecapsule TABLE H contains 12% benzoyl peroxide, curing agent, based on tthe total weight of the diglycidyl ether of bisphenol A Candle ig ig;resin. The other capsule contains an unsaturated poly- Example Numberseconds power integral ester resin curable binder prepared by fusing amixture of 31 140 000 57 500 phthalic anhydride, maleic anhydride andpropylene gly- 2 21 2001000 661000 col forming a compound represented bythe formula 2 e----- e "55666 o 5 23 170,000 52, 200 1 .3 3323 33 t O fis: I 23 1301000 431000 110- oH-oHr-o-o tt-o-on-orr -o-o-rhc H 9 26140.000 48.500

H H 1'1 H What is claimed is: n 1. An improved illuminant composition infree flowing Where n greater than Zero and, 111 afldmon, the capsule l5particulate form comprising an illuminant fuel, oxidizer, contains abqut25 to 35 monomer lc y besed a multiplicity of crushable capsulescontaining a curable the total Welght of the Polyestor Tesm, 5% tltanlombinder for said composition and a multiplicity of crushable oxide, as afiller, and 5% N,N-dimethyl-p-toluidlne, a capsules containing a curingagent for said binder. a cure accelerator, based on the total weight ofthe unsat- 2 The i l i composition f claim 1 wherein the uratedPolyester ratio of curable binder capsules to curing agent capsules Bothcapsules are sold under the trademark PEP-512 is ;1 y National CashRegisttfr PQ 3. An improved illuminant composition in free flowing TheContainers for thls lllllmlnant y be m from particulate form comprisingan illuminant fuel and oxy material normally used for lnuminantcontalnefsidizer, a multiplicity of crusha-ble capsules containing antfirials Preferred are cardboard or metalunsaturated polyester resincurable binder, about 10 to In the illuminant composition theingredients including 0% monomeric Styrene, about 4 to rntile finer andthe illuminant fuel, oxidizer, encapsulated binder, encapabout 4 to onreaeeelerator based on the total Weight Sulated Curing agent, Cureacceletrators and fillers were of the unsaturated polyester resin; and amultiplicity of merely mixed o form Powdered mixturecrushable capsulescontaining a resinous liquid carrier and mgreolonts as lnustratoofnExample? 1 9 Were 10 to 14% curing agent for said binder based on thetotal then dispensed 1nto cardboard canisters approximately 1.2 Weightof the resinous liquid Garden inches in diameter and 2.5 inches long.After dispensing, The composition of claim 3 wherein the illuminant acapsule mpmnog oonsohoaong Pressure of about fuel is selected from thegroup consisting of magnesium, 5,000 p.s.1. was applied by use of apowder consolidating aluminum and Zireenium press- In order toillustrate the performance of the composigg gg g gfii of claim 4 Wheremthe lnummant o of Examples T H illustrates o burning 6. The compositionof claim 3 wherein the oxidizer is trrne, candle power and light mtegralof these luuminant selected from the group consisting of sodium nitrate,lith oomposmons- Normally o Performance should be about ium nitrate,barium nitrate and strontium nitrate.

25 Seconds burn time mmlmum, 125 ooo oandlepowor 40 7. The compositionof claim 6 wherein the oxidizer is and 45,000 light integral. sodiumhirtate To further illustrate the performance of the composi- 8. Thecomposition as in claim 3 wherein the unsat Hons of Examples illuminantPellets approximately urated polyester resin curable binder isrepresented by 1 inch in diameter and 0.75 inch long were made from thef l these compositions by use of a standard die and press. Theconsolidated pressure was approximately 6,000 p.s.i. The 0 uncasedpellets of illuminant were placed in a Riehle testo o o t or and theamount of force necessary to crush these pellets were measured in poundsper square inch (p.s.i). Table I CH CH2 O & gOOH:CH2 O"g C:C\ Hillustrates the amount of pounds per square inch neces- 113 G a H saryto crush these uncased pellets. Normally, 2,000 p.s.i. n minimum isconsidered to be desirable to insure good performance of the illuminant.where n is greater than zero.

Parts by weight (p.b.w.) of- Example Number 1 2 3 4 6 6 7 8 9 Crushablecapsules containing diglycidyl other of bisphenol A resin (Epon 828) and12% benzoyl peroxide, curing agent, based on the total weight of the F512) 2 2 2 3 3 3 4 4 4 Crushable capsules containing unsaturatedpolyester resin (Aropal 72-40-MC) 5% titanium dioxide (filler) and 5%N,N-dimethyl-p-toluidine, cure accelerator based on the total weight ofthe resin. (National Cash Register Corporaresin. (National Cash RegisterCorporation PE tion PEF 512) Magnesium granules (chipped and balled, 50to 200 mesh) Sodium nitrate (crystalline, prilled and ground) TABLE IPellet crush strength, p.s.i.

F. F. F.

Example Number 9. The composition as in claim 3 wherein the styrene ispresent in about 25 to 35% by weight based on the total weight of thepolyester resin.

10. The composition as in claim 3 wherein the rutile filler is titaniumdioxide.

11. The composition as in claim 3 wherein the cure accelerator isN,N'-dimethyl-p-toluidine.

12. The composition as in claim 3 wherein the resinous liquid carrier isa diglycidyl ether of bisphenol A resin represented by the formula wheren is greater than zero.

13. The composition of claim 3 wherein the curing agent is benzoylperoxide.

14. A process for producing a container-cured illuminant comprisingadmixing illuminant fuel particles, oxidizer particles, a multiplicityof crushable capsules containing a curable binder for the particles anda multiplicity of crushable capsules containing a curing agent for saidbinder; dispensing the admixture into a container; and applying acapsule rupturing pressure to the admixture, rupturing the capsules andreleasing and interacting the binder and curing agent within theadmixture in the container, thereby forming the container-curedilluminant.

15. A process for producing a container-cured illuminant comprisingadmixing from about 40 to 60% illuminant fuel particles based on thetotal Weight of the composition, to oxidizer particles based on thetotal weight of the composition, 2 to 8% crushable capsules based on thetotal weight of the composition containing an unsaturated polyesterresin, 10 to 50% monomeric styrene, 4 to 6% rutile filler, and 4 to 6%cure accelera- 25 tor, based on the weight of the polyester resin; and 1to 5% crushable capsules based on the total weight of the compositioncontaining a resinous liquid carrier, and 10l4% curing agent based onthe weight of the resinous liquid carrier; dispensing the admixture intoa container;

21. The process as in claim 15 wherein the oxidizer is selected form thegroup consisting of sodium nitrate, lithium nitrate, barium nitrate andstrontium nitrate.

22. The process as in claim 21 wherein the oxidizer is sodium nitrate.

23. The process as in claim 15 wherein the unsaturated polyester resincurable binder is represented by the formula and applying a capsulerupturing and consolidating pressure to the admixture, rupturing thecapsules and releasing and interacting the binder and curing agentwithin the admixture in the container, thereby forming thecontainer-cured illuminant.

16. The process as in claim 15 wherein the ratio of curable bindercapsules containing the polyester resin, the rutile filler and the cureaccelerator to curing agent capsules containing the resinous liquidcarrier and curing agent is 2: 1.

17. The process as in claim 16 wherein the capsules rupturing pressureis about 5,000 p.s.i. to 7,000 p.s.i.

18. A container-cured illuminant produced by the process of claim 17.

19. The process as in claim 15 wherein the illuminant 50 fuel isselected from the group consisting of magnesium, aluminum and zirconium.

20. The process as in claim 19 wherein the illuminant fuel is magnesium.

where n is greater than zero.

28. The process of claim 15 wherein the curing agent is benzoylperoxide.

References Cited UNITED STATES PATENTS 3,049,454 8/1962 Stark 14923,101,288 8/1963 Courser et a1. 149-21 3,162,559 12/1964 Thomas et a1.14919 3,203,842 8/ 1965 Godfrey 149--19 3,411,963 11/1968 Douda 149-193,454,436 7/1969 Bedell 14919 CARL D. QUARFORTH, Primary Examiner E. A.MILLER, Assistant Examiner US. Cl. X.R.

